Conventionally, there has been an electrophotographic image forming apparatus that includes a developing device including a developing roller and a blade unit for regulating a thickness of a developer layer held on the developing roller. Further, there has been known a blade unit that includes a blade that contacts the developing roller and a supporting member that holds the blade in an overlapping manner.
In the blade unit, the blade and the supporting member are welded to each other at a plurality of locations along the blade in an extended dimension of the blade. Therefore, the blade is formed with a plurality of weld marks spaced apart from each other.